Hello everyone!
After many many sleepless nights tracing the circuit of the SL613 (the SSL Test jig schematic has intentional errors) I'm happy to say that I've managed to recreate it in a 3U rack mounted form.
I've tested it today and all the fuctions of the original test jig work perfectly (4000/6000, Mono, Dual line and stereo channels supported)!
I need to add the fader module to allow it to work with ultimation consoles, the original 613 missed this feature as well.
Some kind of ultimation fader simulator called 354/613 was used to test ultimation consoles, there is very little information about it but it shouldn't be too difficult to recreate.
Does anyone have any information about this very rare ultimation fader jig?
All the best
Michele